Francis it



(No Model.)

P. H. RICHARDS. KNIFE EDGE PIVOT FOB SCALE BEAMS.

No. 559,748. Patented May 5, 1896-.

Witnesses:

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UNITED STATES PATENT muon.

FRANCIS ll. RlCllARDS, OF HARTFORD, (lONNEG'ilClVl.

KNlFE-EDGE PIVOT FOR SCALE-BEAMS.

SPECIFICATION forming part of Letters Patent No. 559,748, dated May 5,1896.

Application filed December 14, 1895. Serial No. 572,184y (No model.)

To (t/ficken?, t may concern:

Be it known that I, FRANCIS ll. RICHARDS, a citizen of the UnitedStates, residing at Hartford, in the county of Hartford and State ofConnecticut, have invented certain new and useful Improvements inKnife-Edge Pivots for Scale-Beams, of which the following is aspecification.

This invention relates to weighingmachines, the object being to providean iniproved scale-beam therefor embodying a removably-supported pivotor knife-edge and a locking device operable for maintaining said pivotor knife-edge against longitudinal and rotative movements When thelatteris in its operative position.

ln the drawings accompanying and forming part of this specification,Figure l is a plan vieriT of one of theloeain-arms of ascale-beainprovided with my improvements and a part ofthe counteriveiglit thereof.Fig. 2 is an end elevation of the saine. Fig. 3 is a detail vieiv inplan of one of the pivots or knifeedges. Fig. l is a transverse sectionon the line a o., Fig. 3.

Similar characters designate like parts in all the ligures of thedrawings.

The general construction of the scale-beam shown in the accompanying'drawings, and

which is designated in a general Way by B, is substantially similar toone of the oppositely-disposed scale-beams shown and described inLetters PatentNo. 54S, S39, granted to mc October 2), 1895, to Whichreference may be had. Each of said scale-beams comprises a pair ofbeam-arms joined by a coinbined conn ecting-shaft and counterpoise,(o11eof these arms being slioivn at 19 and the counterpoise thereof beingslioivn at XV.)

The scale-beam carries a removable pivot or pivots, which aretransversely disposed relatively thereto, and the invention contemplatestlie provision of a locking device or locking devices which are operablefor maintaining said pivot or pivots against rotative and longitudinalmovements when the latter are in the operative positions thereof, asindicated in Figs. l and The beam-arm 19 of the scale-beamisillus`trated removably carrying the two pivots or knife-edges 2 and 3, whichare transversely disposed relatively to said beam -arm and hence to thescale-beam B. The pivot or knife-edge in practice is supported by asuitable beam-support, which is generally carried by the supporting-baseof the Weighing-machine, and the pivot or knife-edge constitutes abucket-support for supporting a suitable bearing carried by the bucketof suoli machine. in practice it is customary to drive these knife-edgesor pivots into position, the idea being to hold thesame tightly in placeagainst movement. ln case the knife-edge becomes dull or blunt fromoontinued use the expenditure of considerable time and labor isnecessary to remove the same for sharpening or grinding, and in case ofbreakage the removal of the bucket is necessary and the use ofmachine-tools is generally required to remove a broken knifeedge orpivot.

By iny invention the knife-edges or pivots are made interchangeable,being removably carried by the scale-beam, so that should it benecessary at any time to remove any one of them for any purpose, Whetherit be for sharpening or to replace a broken one, the application of butslight hand-power is necessary to accomplish this result. The scalebeaniis bored transversely for the reception of these knife-edges or pivots,and the latter are each provided with a cylindrical body portion, whichis located Within said bore, and the latter will be slightly larger indiameter than the diameter of said cylindrical body portion, thedifference in diameters being suoli as to permit the free removal of aknife-edge, but not so great as to induce Wabbling of said pivot When inits operative position. lVlien said pivot or knife-edge is in place inthe transverse bore, a locking device is employed, which is effective inaction and which firmly holds said pivot or knife-edge against rotativeand longitudinal movements relative to the scale-beam or supporttherefor. By this means a structure is provided equal in strength andrigidity to what is termed a driven pivot or knife-edge--that is, onethat is driven or forced into or out of place.

The cylindrical body portions of the tivo knife-edges are shown at 4 and5, respectively, and located Within the correspondingly-shaped bores 4and 5', formed in the beam-arm 19 of the scale-beam B. Each of thecylindrical body portions of the knifeedges or pivots 2 and is shownprovided with a locking notch or recess, the locking-notch for theknife-edge 2 being designated. by (5 and that for the knife-edge beingdesignated by 7, (see Figs. 3 and 4,) the inner wall of which is showncurved for a purpose to be hereinafter described.

The knife-edges are each engaged by a locking device, which is shownconsisting of a disk or locker carried by the scale-beam B. The outerface of the beam-arm 19 is shown having' formed therein the recesses Sand 9, which form seats for ihe Washers or disks 10 and 12 and which arepreferably made cylindrieal, the tivo disks fitting closely Within therecesses 8 and 9, formed in the beam-arm 19. These disks are adapted toenter the lockingnotches 6 and 7, respectively, of the two knifeedges orpivots 2 and 23, and are also seated in the recesses 8 and 9, formed inthe scalebeam, when the parts are in the operative or assembledposition, as shown in 1 and 2, the outer faces of the t\vo disks 10 and12 and the beam-arm 19 being then preferably flush. rlhe perimeter ofthe two disks 10 and 12 is curved, and the curva-ture thereof ispreferably concentric with the inner curved Walls of the locking-notchesG and 7 so that when said disks are in the recesses 8 and 9 of thescale-beam B said pivots or knife-edges 2 and 3, being in theiroperative positions, a portion of the perimeter of said disks 10 and 12Will be in engagement or contact with the inner curved Walls of thelocking-notches 6 and 7 of the two pivots or knife-edges, Wherebyrotative movement of the latter in either direction Will be positivelyprevented, said disks serving practically as fixed abutments.

Some suitable fastening device Will be employed for holding the twodisks 10 and 12 in the operative position thereof, as indicated in Figs.1 and 2, in their recesses orseats and in locked engagement with theknife-edges or pivots 2 and 3 and against lateral movement relative tothe beam-arm 19, thereby also holding the pivots or knife-edges 2 and 3against longitudinal movement. The means illustrated for this purposeare the holdingscrews 13 and 1-1, which enter centrallyformed openingsin said disks, said screws being also seated in screw-threaded openingsformed in the scale-beam B.

To remove one of the knife-edges-for example, the knife-edge 2-theholding-screw 13 is Withdrawn from place, at which time the knife-edgemay be grasped by the hand and easily pulled from its bore in thescale-beam, this action also withdrawing the locking-disk 10 therewith.To replace the knife-edge, the locking-disk 10 will be inserted in itslockingnotch 6 and the knife-edge 2 will be passed through the bore 4Cand its locking-disk 1() into its recess or seat S in the scale-beam B.Then the parts are in the assembled positions, as shown in Figs. 1 and2, the screw 13 is driven into place by some suitable instrument, sothat when the pivot or knife-edge 2 is in place in the scale-beam thelocking device 10, carried bythe latter, firmly holds the same againstrotative and longitudinal movements.

Having thus described my invention, I claim- 1. The combination with ascale-beannof a pivot removably carried by said scale-beam, saidy pivothaving a notch formed in one side thereof; and a locking device carriedby the scale-beam and seated in said notch.

2. The combination with a scale-beam, of a pivot removably carriedthereby, said pivot having a locking notch provided with a curved Wall;and a locking device operable for engaging said curved Wall.

3. The combination with a'scale-beam, of a pivot removably carriedthereby, said pivot having a locking -noteh provided With a curved Walland a circular disk for engaging said curved Wall, and having thecurvature of said disk concentric with said curved Wall, whereby saidpivot Will be held against rotative movement by said disk.

f1. The combination with a bored and recessed scale-beam, of a pivotlocated in said Abore and provided with a locking-notch; a

locker located inthe recess of the scale-beam and seated in said notch;and a fastening device for holding said locker in place in said recess.

FRANCIS Il. RICHARDS. lVitnesses:

FRED. J. DOLE, R. XV. PITTMAN.

